Mystery over the SEVEN-MILE long 'super mega-pod' of 100,000 dolphins spotted off the coast of San Diego

A group of over 100,000 dolphins spotted off the coast of San Diego caused a spectacle for nature watchers as they traveled together in an enormous pack.

'They were coming from all directions, you could see them from as far as the eye can see,' Joe Dutra said after seeing the spectacle first hand.

Mr Dutra, who captains Hornblower Cruises, was out on his daily tour with a boat full of nature watchers when he spotted the massive group of dolphins.

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Massive group of mammals: A ship captain spotted a group of 100,000 dolphins swimming together off the coast of San Diego on Thursday and experts are unable to give a specific reasoning for why such a large group would be there

'I’ve seen a lot of stuff out here… but this is the biggest I’ve ever seen, ever,' he told the local NBC affiliate.

Dolphins typically travel in groups of anywhere between 15 and 200 which are called pods.

What Mr Dutra spotted on Thursday however is best described as a super mega pod given the astonishing size of the group.